Powered reciprocating saws include jigsaws and other reciprocating saws which are referred to in the trade as "recipro" saws. These saws employ linear saw blades which are reciprocated along a rectilinear path.
The saw blades used with these powered saws typically include a hole in the end of the blade opposite the working end of the blade. The power tools under consideration typically include a blade holder having a slot for receiving the saw blade and a set screw which is received in the hole in the blade. This set screw must be tightened to clamp the blade in place in the blade holder. Although this form of blade holder is generally satisfactory, it does suffer from the disadvantage in that the blade is likely to become loose during operation of the tool unless the set screw has been made very tight. As is known to those skilled in the art, powered saws of the type under consideration are subject to high vibration forces during use. A further disadvantage with the type of blade holder under discussion resides from the fact that tightening and loosening of the set screw necessarily prevents the very rapid change of blades. An even further disadvantage of this type of blade holder is the requirement of a separate tool for fixing and removal of the blade.
Attempts have been made to provide saw blade holders which do not require the use of a set screw. One example of such a blade holder is shown in U.S. Pat. No. 3,927,893, assigned to the assignee of the present invention. The blade holder shown in this patent includes a cap which is threadingly engaged with the plunger of the power tool. Rotation of the cap relative to the plunger in one direction causes axial movement of the cap for squeezing a member against the blade to hold the latter in place. Rotation of the cap in the other direction serves to release the blade. Operation of this device requires rather significant rotational forces for both securing the blade in place and loosening of the blade for separation from the tool, often requiring the use of a wrench.
Other attempts to secure reciprocating saw blades in place without the use of a set screw are represented by Hoffman U.S. Pat. Nos. 3,750,283, 4,204,692 and 4,285,129. For the most part, the devices shown in these patents are complicated and expensive to produce because they employ many separate parts. Further, the blade holders disclosed in these patents require special saw blades having notches or recesses in their edges to cooperate with various projections forming part of the blade holder mechanism.
The present invention provides a new and improved blade holder which can accommodate conventional saw blades and which can hold the saw blade in place without the use of set screws and without employing any form of a tool. According to the present invention, the saw blade can be mounted in place and detached using only finger pressure.
It is a primary object of the present invention to provide a new saw blade holder of the type described.
A further object of the present invention is the provision of a saw blade holder which does not require the use of the set screw or any form of a fastening tool.
Still another object of the present invention is the provision of a new and improved blade holder which is of simple construction and which can be manufactured at low cost.
These and other objects and advantages of the invention will become apparent from the following specification disclosing preferred embodiments.